Npower is most complained-about energy firm, receiving eight times the number
of complaints as its best performing rival

Npower continues to receive the largest number of customer complaints, according to new figures from Consumer Futures.

The data showed that npower received 253 complaints per 100,000 customers between July and September last year, around eight times more than the best performing company.

SSE recorded the lowest rate of complaints, at 32 per 100,000 customers, followed by Scottish Power (46), British Gas (55), e.on (62) and EDF Energy (74).

Npower was also the most complained-about energy company in the data compiled from April to June last year. The company blamed the switch to a new billing system.

Audrey Gallacher, director of energy at Consumer Futures, said: "While npower has acknowledged and apologised for its poor billing systems and agreed to pay vulnerable customers who have been disadvantaged, its deterioration in performance is still wholly unacceptable and the company must address the failure of its systems, processes and customer service to put things right."

The analysis is complied with data from the Citizens Advice service, the energy ombudsman and Consumer Futures, a government-backed regulator watchdog that was formerly called Consumer Focus.

Its findings follow disclosures by the Telegraph last month. A whistleblower claimed call centre staff were put under undue pressure to end calls within an alloted time and that exacerbated its customer service problems.

It also suffered from a failure of its computer systems last year, which affected around 700,000 customers, leaving many with inaccurate bills. It agreed a settlement with the regulator Ofcom, paying £1m towards a fund for vunlerable customers.

Citizens Advice chief executive Gillian Guy said: "With people paying such a high price to have a warm home or keep the lights on the service provided by energy companies should be exemplary, but all too often we’re finding that’s not the case."

Roger Hattam, director of domestic retail business at npower, said: "Last year, we apologised to our customers for the service issues they may have faced, following the installation of a new billing system.

"We're working on these issues as top priority and, while we still have a long way to go, we're making good progress. Our customers deserve to get the best service possible and this is my commitment to them."